Abstract Number: PB0304
Meeting: ISTH 2020 Congress
Background: Anti-Xa levels and activated partial thromboplastin time ratios (APTTr) are suggested as methods for monitoring unfractionated heparin infusions (UFH) during Extracorporeal Membrane Oxygenation (ECMO). It is unclear which method of monitoring is most appropriate to prevent systemic thromboembolism and circuit thrombosis.
Aims: To compare clinical and therapeutic outcomes of patients receiving APTTr and anti-Xa monitoring during ECMO.
Methods: We performed a prospective audit of patients receiving ECMO from 03/09/19 to 03/11/19 using APTTr and 04/11/19 to 04/11/20 using anti-Xa. APTTr targets of 1.5-2.0 or anti-Xa of 0.3-0.7 were used for those without thrombosis (prophylactic) and APTTr 2.0-2.5 or anti-Xa 0.7-1.0 with thrombosis (treatment). Low-dose fixed rate infusions were used in those with high bleeding risk. Values were excluded during fixed rates or no heparin. Targets were adjusted at clinicians´ discretion. Statistical analysis was performed by two-tailed Mann-Whitney U test with significance level p< 0.05.
Results: 14 patients were identified in each group. Bacterial and viral pneumonias were the most common underlying diagnoses (n=8 vs 9) for APTTr and anti-Xa respectively. Other characteristics are shown in Table 1. The mean number of monitoring tests per patients’ ECMO duration for APTTr was 31 (2.5/day) versus 13 for anti-Xa (1.5/day) (p=0.026). The mean number of UFH dose changes was 7 vs 5 and time-in-target range was 40.7% vs 60.8% (p=0.038). Blood product usage was similar between both groups. Arterial and venous thrombosis during ECMO occurred in 4 vs 1 and deep vein thrombosis after decannulation occurred in 5 vs 1 in APTTr vs anti-Xa. Major bleeding occurred in 4 vs 1 for APTTr vs anti-Xa respectively.
Conclusions: Initial data from a small cohort suggests anti-Xa may provide a lower frequency of testing, higher time-in-target ranges and lower rates of thrombosis during ECMO over APTTr. This study needs further replication in larger patient groups to confirms these findings.
|Mean duration of ECMO (days)||14||9|
|Mean SOFA Score at presentation||11||14|
|Mean Platelet Count (x10^9/L)||133||128|
|Number of patients with each Anticoagulation Target (prophylactic, therapeutic, fixed rate, no heparin)||9, 2, 2, 1||7, 1, 6, 0|
[Characteristics of patients receiving ECMO according to unfractionated heparin monitoring]
To cite this abstract in AMA style:Doyle AJ, Pandey M, Shah R, Breen KA, Barrett N, Hunt BJ, Retter A. Outcomes of Patients with Anti-Xa versus APTTr Monitoring for Unfractionated Heparin Infusions during Extracorporeal Membrane Oxygenation [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/outcomes-of-patients-with-anti-xa-versus-apttr-monitoring-for-unfractionated-heparin-infusions-during-extracorporeal-membrane-oxygenation/. Accessed December 3, 2021.
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